Spool



FIG. 1 is a perspective view of a spool of the present invention;

FIG. 2 is a top view of the spool of FIG. 1;

FIG. 3 is a front side view of the spool of FIG. 1, the left, right and rear side views being identical; and,

FIG. 4 is a bottom view of the spool of FIG. 1.

The broken lines in the drawings illustrate portions of the spool which form no part of the claimed design. 

CLAIM The ornamental design for a spool, as shown and described. 